Impact tools



E. SUSSMAN IMPACT TOOLS Aug. 23, 1966 2 Sheets-Sheet 1 .y

Filed Feb. 18. 1964 INVENTOR MMM ATTORNEYS United States Patent Office 3 ,268,013 Patented August 23, 1966 3,268,013 IMPACT TOOLS Ernst Sussman, Bierys Bridge Road, Bethlehem, Pa. Filed Feb. 18, 1964, Ser. No. 345,777 12 Claims. (Cl. 173-53) This invention relates to impact tools for manual application to a 4piece of work, a tool of this description including a spring-propelled hammer member, a handle grip, and means for cocking the tool for release of the hammer member for impact upon application of pressure to the handle grip.

The present invention is of the same general nature as the one covered in my co-pending application Serial No. 151,970, led on November 13, 1961, now Patent No. 3,181,626, but has for its principal object the provision of readily manipulatable means for adjusting the force of the spring propulsion of the hammer.

Another object of the invention -is the provision of a novel and improved re-cocking spring arrangement with pivoted engaging elements, permitting some advantageous simplification of the construction of the tool.

In its preferred embodiments, the invention contemplates the provision of two springs which together furnish the propulsion power for the hammer; one of the springs being of a fixed spring rate and bodily replaceable by or interchangebale with springs of other predetermined rates, and the `other of `said springs being subject to variable degrees of initial or effective compression adjustable by a simple rotation of the hammer assembly. However, only one of these springs oifers resistance to either manual or automatic re-cocking.

Other objects and features of novelty will be apparent from the following specication when read in connection with the accompanying drawings in which one embodiment -of the invention is illustrated by way of example.

In the drawings: Y

FIGURE 1 is a view in angular axial section as along section line I-I of FIGURE 3, of an impact tool embodying the principles of the invention, the .parts being in manually cocked position awaiting the delivery of the hammer blow by the application 'of pressure to the handle grip portion of the tool;

FIGURE 1A is a similar view of the same tool with the pivoted elements set as for automatic re-cocking for repeat action;

FIGURE 2 is a View in axial section taken at 90 rotation from the view in FIGURE l;

FIGURE`3 is a View in transverse section taken on line 3 3 of FIGURE 2;

FIGURE 4 is a fragmentary exploded view in perspective illustrating the intertting relationship of a guide member and an adjusting nut carried by the hammer;

FIGURE 5 is a view similar to FIGURE 1 showing the adjusting nut travelled along the shank of the hammer to increase the initial compression of one of the hammer projecting springs;

FIGURE 6 is a View similar to FIGURE 2 and taken at right angles with respect to FIGURE 5, showing the positions of the parts at the instant of release of the hammer trigger;

FIGURE 7 is a view similar to FIGURE 6 showing the -positions of the parts at the moment of impact of lthe hammer with the anvil member; and

FIGURE 8 is a view similar to FIGURE 7 but with the pivoted elements in position with respect to the recocking spring to provide for repeat action.

The novel impact tool illustrated in the drawings is indicated by the general reference numeral 10 and is seen to comprise a body assembly 11 and a handle grip assembly 12, the handle grip assembly comprising the sleeve-13 which surrounds and is slidable along the barrel 14 `of the body assembly. The handle 12 also in- -cludes the base element 15 which comprises a bushing threaded into the sleeve 13 as at 16.

Another fixed por-tion of the body assembly is the guide member which is threaded into the rearward portion of the barrel 14 as at 21.

An anvil is slidingly received within a widened cylindrical portion 26 of the barrel 14 and is urged rearwardly toward a retracted position by means of the spring 27, the spring seating forwardly against the nose piece 28 threaded as at 29 into the forward end of the barrel 14. A stem 30 carried by the anvil 25 extends through an axial opening in the nose piece 2S and is provided with a suitable socket 31 or other meansl for connecting a toolbit thereto.

A hammer 35 is slidably received within the cylindrical portion 36 of the barrel 14, this portion is of a smaller diameter than the portion 26 providing a shoulder 38 against which the wider portion of the anvil 25 abuts in its retracted position. The hammer 3S has an impact face 40 which is adapted to strike the face 41 of the anvil to impart the driving force to the tool.

The hammer 35 is provided with a shank portion of stepped configuration, a larger cylindrical portion 42 bein-g surrounded by a coil spring 44 which is compressed lbetween the rear shoulder of the hammer proper and the forward end -of the guide member 20. A still further attenuated shank portion of the hammer designated 45 is slidingly received within the bore 47 of .the guide 20 and the shoulde-r 46 between the portions 44 and 45 provides an abutment `limiting the rearward movement of the hammer 35.

Finally, the shank portion 45 terminates in a frustoconical end portion 48, an annular groove 50 being formed in the surface of the shank `adjacent the junction of the portion 45 and the tapered portion 48.

The shank of the hammer is provided with a threaded bore 52 for the reception of the forward threaded end 54 of the adjustment screw 55. This adjustment screw 55, which also acts as a tractive means Afor the hammer as will be explained, is guided through an opening 56 in the forward portion lof the handle bushing 15 and terminates in a head 57 provided with a slot 58 for the application of a suitable tool for rotating the adjustment screw 55. The head portion 57 is received within a cylindrical recess 60 of the bushinlg 15 which recess is closed by a removable plug 61.

The guide member 20 will now be described in considerable detail and in this connection it might be well to compare this member with its counterpart designated by the numeral 12 in the co-pending application Serial No. 151,970. The portion of the member 20 which is of the greatest diameter is indicated at 63 and this presents a shoulder between which and the rearward end of the barrel an annular cam element 65 is rotatably positioned. This element cor-responds exactly to its counterpart 14 shown most clearly in FIGURE 4 of the application above referred to and performs the same function, being actuated by means `of the sliding member 66 which works in the groove 67 formed in the outer surface of the rearward portion ofthe banrel 14.

lust `as -in the case of the embodiment disclosed in the co-pending application, this cam element 65, by means of the rotation of the handle 12 with respect to the body portion 11, controls the rocking of the pivoted elements 70 by acting upon the forward ends 71 o-f these elements to shift them from the position shown in FIGURE ,1 to the position shown in FIGURE 1A, the effect of which o Y a is to convert the operation of the tool from single impact to repeat action. The details of this operation will be described later.

As previously described, Athe forward end of the guide member 2i) provides a rear spring seat for the spring 44 and also an abutment for the shoulder 46 of the shank of the hammer. Rearwardly, as best shown in FIGURE 4 of the drawings, the member 20 is provided with an elongated slot 72 to accommodate the swing-ing of the latch or trigger member 75.

Di-ametrically opposite the slot 72 is a tapered groove 76 which, together with the other two tapered grooves 77 and 78, accommodates the pivoting of the pivoted elements 70, these grooves being preferably disposed 120 apa-rt. Two other slots 80 are ,formed in the rearward portion of the guide member 20 to accommodate the .wings 82 of the spring compression adjusting nut S5 threaded on the shank 54 of the screw 55.

Between the rear surface of the nut 85 and the forward end of the f-rusto-conical portion S6 of the base member 15 of the handle is compressed a second hammer-projecting spring 88 which when the hammer is released cooperates with the spring 44 to drive the hammer 35 forwardly to strike the anvil v25.

The latch or .trigger member 75 has a forward fulcrumed end portion 89 and an intermediate tooth 90, and a small coil spring 92 serves to urge the member 75 radially inwardly to engage the tooth 9i# within the annular groove 94 formed in the shank of the hammer adjacent the junction of the tape-red portion 48 and the intermediate shank portion 45. The extreme end 95 of the latch member bears against the tapered wall of the frusto-conical base portion 86 and it will be seen that upon forward movement of the handle 12 upon .the body 11 the wedging action of the tapered portion 86 will swing the llatch 75 outwardly until it reaches the position shown in FIGURE 6 of the drawings, whereupon the tooth 90 will disengage from the [groove 94 and the springs l44 and 88 will propel the hammer forwardly to strike the anvil 25 and deliver the predetermined blow to the work.

Internally of an intermediate port-ion of the handle sleeve 13 are a series of arcuate inwardly projecting lugs 97, and between these lugs and the forward face of the larger portion of the base member 15 of the handle is compressd a coil spring 160. For single or one-shot action, the rotated position of the handle with respect to the body of the tool is set according to the disclosure in the co-pendinig application Serial No. 151,970, now Patent No. 3,181,626 and lthe annular ca-m member 65 permits the pivoted elements 70 to occupy the positions shown in FIGURES 1, 2, 5, 6 and 7 where the garter spring 161 retains the *latches in their radially inwardly retracted positions. However, upon proper rotation lof the handle with respect .to ,the body of the tool, again in accordance with the procedure described in the co-pending application, the cam member 65 acting upon the forward smaller ends 71 of the elements 70 lipiyots them around the fulcrum provided by the inclined portion of the slots 76, 77 and 78 and brings the heads of the elements 7 outwardly against the inner Wall of the sleeve 13 of the handle into the positions shown in FIGURES 1A and 8 of .the drawings. This br-ings them into alignment with the re-cocking spring 100 which is utilized under these condition-s to automatically re-cock the hammer for repeat action as will be described.

The operation of the tool for both single and repeat action is as follows.

After a single action operation of the tool the parts will be in the positions shown in FIGURE 7 of the drawings and if the anvil shank 30 is secured as at 3l to a bit having a pull-back connection with the work, the handle 13 is merely pulled rearwardly, which through the connection with the hammer 35 by means of the head 57 of the tractive screw element 55 will draw the hammer rearwardly, compressing the forward propelling spring 44 until the .latch 75 sliding down the rfusto-conical surface of the handle part 86 permits the tooth 90 to re-engage the .annular groove 59 in the hammer shank. The parts will now be in substantially the positions shown in FIGURES 1, 2 and 5 of the drawings.

Under these conditions the rearward pull of the handle against the tension of the spring 44 will test the connection upon which the tool has acted, in the same manner as described in the co-pending application.

If the tool has no pull connection with the work then the handle will have to be retracted manually by an outward pull upon both the body portion 11 and the handle 12 until the tool is in cocked position as in FIGURES 1 and 2` or 5.

Before continuing with the description of the projection of the hammer, it will be well to describe one of the principal novel features of the present invention, namely, the means for adjusting the etfective strength of the rearward propelling spring 88. In FIGURES 1 and 2 of the drawings the nut S5 is practically in its extreme forwardly adjusted position either abutting or about to abut the rear end of the tapered portion 48 of the hammer shank and under these conditions the spring 88 is at its maximum elongation.

Now in order to increase the initial compression of the spring 88 and thus the ultimate force of the hammer blow, the plug 61 is removed from the handle base element 15 and a screwdriver or other tool applied to the slot 58 in the head 57 of the adjusting screw 55. Then upon rotating the screw 55 clockwise the screw will thread its way through the nut and into the threaded bore 52 of the shank portion 45 of the hammer until the shoulder 46 of the shank portion 42 is pulled tightly against the forward end of the mem-ber 20. Further turning of the adjusting screw 55 will now force the nut 85 back against the spring 84S thereby increasing the spring force of that propelling spring. The hammer 35 and its shank portions will then turn with the screw 55 while the nut S5 can only move in the axial direction out of the grooves 80 of the guide member 20.

This adjustment is carried to the desired point to regulate the .force of the spring 88 and one such adjusted position is shown in FIGURE 5 of the drawings where it will be seen that the nut has receded from the end of the member 20 and has compressed the spring 88.

Now, whatever the point of adjustment of the rearward propelling spring 88, whether as shown in FIGURES l and 2 or as further compressed in FIGURE 5, the point of the tool is applied to the work and the handle 12 is manually moved forwardly, the finger of the latch 75 riding up on the release taper of the portion 86 until the tooth 90 is released from the groove 94, this instantaneous position being shown in FIGURE 6 of the drawings. This triggers the hammer and under the influence of both the forward spring 44 and the rearward spring 88 the hammer 35 is projected forwardly to strike the anvil 25 as shown in FIGURE 7 of the drawings.

From the position shown in FIGURE 7 the tool is returned to operative position for single .action as previously described.

Now for repeat action, the handle 12 is turned so that the cam 65 swings the pivoted elements 70 from the positions shown in FIGURES 1, 2, 5, 6 `and 7 to the positions shown in FIGURES 1A and 8 where the heads of the elements 70 are aligned with the spring 100` just beyond the stop projections 97. In delivering the impact the handle is pressed forwardly as in the case of single action operation, the latch or trigger 75 is released as before, and the blow is delivered as indicated in FIGURE 8 of lthe drawings. During the forward movement of the handle not only is the spring 88 compressed but the re-cocking spring is also compressed against the heads of the pivoted elements 70. Now when the blow is delivered as in FIGURE 8, the force of the spring 100 overcomes the opposing force of the forward propeiling spring 44 when the pressure on the handle is relieved, .thereby returning the handle to cocked position and re-compressing the spring 44. Of course, the spring 88 is merely used in .applying a regulated impact force, which is the result of the relatively fixed force of the spring 44 plus the variable force of the spring 88. Thus, the tension of spring 8S does not enter into the force pattern for returning the handle.

It will be understood that a coarse adjustment of the impact force may be attained by the substitution of interchangeable springs 44 of different rates, and a finer adjustment of this impact force can be attained by the rotation of the screw 5S applying a variable compression force to the rearward propelling spring 88.

Various changes and modifications may be made in the embodiment illustrated and described yherein without departing from the scope of the invention as defined by the following claims.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

1. An impact tool comprising a hollow tubular body member, an anvil slidably disposed within said body member and having a stem projecting forwardly from the body member to carry a tool-bit, a hammer slidably disposed within said body member rearwardly of said anvil, a hammer-projecting spring disposed for compression between said hammer and a portion of said body member and urging said hammer toward said anvil, a handle member carried by said body member and movable longitudinally with respect thereto, a lost motion connection between said hammer and said handle member whereby retractive movement of said handle member will pull said hammer rearwardly and compress said projecting spring -whilst the handle member may be moved in the forward direction independently of said hammer, a compression spring disposed between said handle member and said hammer urging the hammer and handle member apart to take up the slack of the lost motion connection, and means for cocking the hammer and tripping it to project it to- Ward said anvil.

2. An impact tool comprising a hollow tubular body member, an anvil slidably disposed within said body member and having a stem projecting forwardly from the body member to carry a tool-bit, a hammer slidably disposed within said body member rearwardly of said anvil, a hammer-projecting spring disposed for compression between a rearward-ly facing portion of said hammer and a forwardly facing portion of said body member and urgin-g said hammer toward said anvil, a handle member carried by said body member extending rearwardly thereof and movable longitudinally lwith respect thereto, a lost motion connection between said hammer and said handle member, a second spring disposed for compression between a rearwardly facing portion of said hammer and a forwardly facing portion of said handle member, and means for cocking the hammer and tripping it to project it toward said anvil.

3. The impact tool as set forth in claim 2 in which the rearwardly facing portion of the hammer against which said second named spring bears is adjustable longitudinally of the tool with respect to the handle member to apply a predetermined initial compression to the spring.

4. An impact tool comprising a hollow tubular body member, an anvil slidably disposed within said body member and having a stem projecting forwardly from the body member to carry a tool-bit, a hammer slidably disposed within said body member rearwardly of said anvil, a hammer-projecting spring disposed for compression between said hammer and a portion of said body member and urging said hammer toward said anvil, a handle member carried by said body member and movable longitudinally with respect thereto, a lost motion connection between said hammer and said handle member whereby retractive movement of said handle member will pull said hammer rearwardly and compress said projecting spring whilst the handle member may be moved in the foriward direction independently of said hammer, a compression spring disposed between said handle member and said hammer urging the hammer and handle member apart to take up the slack of the lost motion connection, and latch means for retaining said hammer in cocked position upon retraction of the handle to a certain point of compression of said first named spring, and trip means for releasing said latch means actuated by forward movement of the handle beyond a certain point of compression of said second named spring, whereby the propulsive force of said second named spring is added to that of said first named spring in projecting the hammer against the anvil and toolJbit.

`5. The impact tool as set forth in claim 4 in which means are provided for varying the initial compression of the second spring to apply variable propulsive forces to said hammer in addition to the force supplied by said first spring in projecting the hammer toward the anvil.

6. An impact tool comprising a hollow tubular body member, an anvil slidably disposed within said body member and having a stem projecting forwardly from the body member to car-ry a tool-bit, a hammer slidably disposed within said body member rearwardly of said anvil, a hammer-projecting spring `disposed for compression between a rearwardly facing portion of said hammer and a forwardly facing portion of said body member `and urging said hammer toward said anvil, a handle member carried by said body member extending rearwardly thereof and movable longitudinally with respect thereto, a lost motion connection between said hammer and said handle member whereby retractive movement of said handle member will pull said hammer rearwardly and compress said projecting spring whilst the handle member may be moved in the forward direction independently of said hammer, a second compression spring disposed between said handle member and said hammer urging the hammer and handle member apart to take up the slack of the lost motion connection, and a third spring disposed for compression between a rearwardly facing portion of said body member and a forwardly facing portion of said handle member, and means for effecting or interrupting the contact of said third spring with said body member at will, and means for cocking the hammer and tripping it to project it toward said anvil, said third spring assisting in effecting the relative retractive cocking -movement between the handle member and the hammer on the one hand and the body member on the other.

7. An impact tool comprising a hollow tubular body member; an anvil slidably disposed within said body member and having a stem projecting lforwardly from the b=ody member to carry a tool-bit; a hammer slidably disposed within said body member rearwardly of said anvil; a hammer-projecting spring disposed for compression between a rearwardly facing portion of said hammer and a forwardly facing portion of said body member and urging said hammer toward said anvil; means for releasably latching said hammer to said body member upon retraction of the hammer .a predetermined distance against the expansive tendency of said spring; a handle member carried by said body member, extending rearwardly thereof, and movable longitudinally with respect thereto; a lost motion connection between said hammer and said handle member whereby retractive movement of said handle member will pull said hammer rearw-ardly and Vcompress `s-aid projecting spring whilst the handle member may be moved in the forward direction independently of said hammer; .a second compression spring disposed between said handle member land said hammer urging the hammer `and handle member apart to take up the -slack `of the lost motion connection and resisting forward movement of said handle; means on said handle member for releasing said latching means upon forward movement ofthe handle member; an abutment, adjustable `along said hammer, .against which said second spring 'i7 seats; and means for adjusting the position of said abutment to vary the initial compression of said second spring and thus the propulsive force exerted on said hammer by said second spring upon such forward movement of the handle member.

S. An impact tool comprising a hol-low tubular body member; an anvil slidably disposed within said body member and having a stem projecting forwardly from the body member to carry a tool-bit; a hammer :slidably disposed within said body member rearwardly of said anvil, and having a threaded stem portion extending rearwardly through and beyond said body portion; a hammer-projecting spring disposed for compression between a rearwardly facing portion of said hammer and va forwardly facing portion of said body member, and urging said hammer toward said anvil; means for releasably -latching said hammer to said body member upon retraction of the hammer a predetermined distance against the expansive tendency of said spring; a handle member carried by said body member, extending rearwardly thereof, and movable longitudinally with respect thereto; a lost motion connection between said stem -portion on said hammer and said handle member, whereby ret-ractive movement of said handle member will pull said hammer rearwardly and compress said projecting spring whilst the handle member may be moved in the forward direction independently of said hammer; a second compression spring disposed between said handle member and said hammer urging the hammer and handle member apart to take up the slack of the lost motion connection, and resisting forward movement or" said handle; means on said handle member for releasing said latching means upon forward movement of the handle member; an abutment element threaded on said stern portion, for adjustment therealong, against which said second spring seats; and means for rotating said hammer to adjust the position of said abutment element to vary the initial :compression of the second spring and thus the propulsive force exerted on said hammer by said second spring upon such forward movement of the handle member.

9, An impact tool comprising a hollow tubular body member; an anvil slidably disposed within said body member and having a stem projecting forwardly from the body member to carry a tool-bit; a hammer slidably disposed within said body member rearwardly of said anvil, having la threaded stem member screwed into the main portion of -the hammer and extending rearwardly beyond said body portion; a hammer-projecting spring disposed lfor compression between a rearwardly facing portion of said hammer and a forwardly facing portion of said body member, and urging said hammer toward said anvil; means carried by said body member for releasably latehing said hammer thereto upon retraction of the hammer a predetermined distance yagainst the expansive tendency of said spring; a tubular handle member telescoping u-pon said body member, extending rearwardly thereof, and movable longitudinally with respect thereto; a lost motion connection between said stem member and said handle member, whereby retractive movement of said handle member will pull said hammer rearwardly and compress said projecting spring whilst the handle member may be moved in the forward direction independently' of said hammer; an abutment element threaded on said stem portion for ladjustment therealong; a second compression spring disposed .between said handle member and said abutment element urging the hammer and handle member apart to take up the slack of the lost motion connection, and resisting forward movement of said handle; means on said handle member for releasing said latching means upon forward movement of the handle member; and means for rotating said stem member to adjust the position of said abutment element therealong to vary the initial compression of the second spring and thus the propulsive force exerted on said hammer by said second spring upon such forward move ment of the handle member.

10. The impact tool as set forth in claim 9 in which said tubular handle member terminates outwardly of said body member in an end wall, and in which there is provided ian opening in said end wall through which said threaded stem member extends, `and -a head on the end of said stem member outwardly of said opening.

11, The impact tool as set forth in claim 10 in which a recess is provided in said end wall outwardly of said opening -of sufficient depth to afford :adequate movement of said head to correspond to the relative movement of said hammer and said Ihandle during operation. 12. The impact tool .as set -forth in claim-11 in which there is provided a removable plug for the closure of said recess and means on the head of said stem member for the application of a tool to rotate said stern member.

References Cited by the Examiner UNITED STATES PATENTS 1,190,657 7/1916 Kollock et al. 173T119 2,907,241 10/1959 LaZar 173-.,119 2,976,608 3/1961 Busler 173--119 3,071,994 1/1963 Swenson 173-121 3,074,155 1/1963 Cootes et al. 173-119 MLTON KAUFMAN, Primary Examiner. L. P. KESSLER, Assistant Examiner. 

1. AN IMPACT TOOL COMPRISING A HOLLOW TUBULAR BODY MEMBER, AN ANVIL SLIDABLY DISPOSED WITHIN SAID BODY MEMBER AND HAVING A STEM PROJECTING FORWARDLY FROM THE BODY MEMBER TO CARRY A TOOL-BIT, A HAMMER SLIDABLY DISPOSED WITHIN SAID BODY MEMBER REARWARDLY OF SAID ANVIL, A HAMMER-PROJECTING SPRING DISPOSED FOR COMPRESSION BETWEEN SAID HAMMER AND A PORTION OF SAID BODY MEMBER AND URGING SAID HAMMER TOWARD SAID ANVIL, A HANDLE MEMBER CARRIED BY SAID BODY MEMBER AND MOVABLE LONGITUDINALLY WITH RESPECT THERETO, A LOST MOTION CONNECTION BETWEEN SAID HAMMER AND SAID HANDLE MEMBER WHEREBY RETRACTIVE MOVEMENT OF SAID HANDLE MEMBER WILL PULL SAID HAMMER REARWARDLY AND COMPRESS SAID PROJECTING SPRING WHILST THE HANDLE MEMBER MAY BE MOVED IN THE FORWARD DIRECTION INDEPENDENTLY OF SAID HAMMER, A COMPRESSION SPRING DISPOSED BETWEEN SAID HANDLE MEMBER AND SAID HAMMER URGING THE HAMMER AND HANDLE MEMBER APART TO TAKE UP THE SLACK OF THE LOST MOTION CONNECTION, AND MEANS FOR COCKING THE HAMMER AND TRIPPING IT TO PROJECT IT TOWARD SAID ANVIL. 